This study was initiated to determine whether exposure to technical pentachlorophenol (tPCP) by the cutaneous route affects the liver; to compare the effectiveness of the cutaneous versus the oral route on hepatic mixed function oxidases (MFO's); and to compare pure versus technical pentachlorophenol to ascertain whether effects on MFO's are due to pentachlorophenol or to its contaminants, the dibenzodioxins and dibenzofurans.